The present invention relates to an active matrix liquid crystal display device having a liquid crystal capacitor and a storage capacitor arranged parallel to the liquid crystal capacitor in units of pixels arrayed in a matrix.
In recent years, active matrix liquid crystal display devices using a TN crystal have advanced in screen size and resolution, and a high image quality is obtained for static images. For motion images, however, no satisfactory characteristics are obtained in general, though the devices are being improved by developing a fast response material or signal processing circuit.
As an improvement by signal processing, a driving method has been proposed in, e.g., Jpn. Pat. Appln. KOKAI Publication No. 4-288589 in which, for a motion image with a change in pixel potential, the voltage to be applied to the liquid crystal is corrected in advance to emphasize the change, thereby improving the image-lag characteristic of the motion image. In this driving method, R, G, and B image signals of one frame are stored in a frame memory. To detect motion of an image between two continuous frames, the difference between the image signal of one frame and that of the next frame is detected by a subtracter. This difference signal is multiplied by a predetermined coefficient .alpha. by a multiplier to emphasize the change. This emphasized signal is added to the current signal by an adder to obtain a change emphasized signal. This change emphasized signal is supplied to a signal line driver to drive the signal line of the liquid crystal panel. The gate line of the liquid crystal panel is driven by a gate line driver. The signal line driver and the gate line driver are controlled by the outputs from a control signal circuit which operates upon receiving a sync signal.
However, since this driving method requires, as part of the signal processing circuit, a frame memory or field memory for storing image signals of one frame, the manufacturing cost, mounting area, or power consumption undesirably increases.